APPARATUS AND METHOD FOR REMOVING DISTURBANCE

摘要

PURPOSE: An apparatus and a method for removing disturbance are provided to efficiently remove periodical disturbance by applying a DOB or an MA-DOB, thereby stabilizing tracking and focus servos. CONSTITUTION: A sensor K(S)(10) outputs tracking and focus error signals related to a track center and a pick-up position. A controller C(S)(11) outputs a compensating signal following reference up and down positions and reference right and left positions of a pick-up. An actuator P(S)(13) receives a final compensating signal having removed periodical disturbance for writing data on tracks of a recording medium, or changes the position of the pick-up operating in reading the data. An MA-DOB(Modify-Disturbance OBserver)(40) outputs a compensating signal having removed periodical disturbance from the tracking and focus error signals and the former final compensating signal. A switch(40-2) switches operations of the MA-DOB.